Well, yeah an empty theme won't be overriding the properties, so they would still fall back to inheriting from the top.
You have to click on 'Manage Items' in the theme editor area. Next, in the overlay window that opens click on the tab you are after, Default Theme, or if you actually meant the Editor Theme then on that tab. Then in chosen tab, at the bottom you should see a button called 'Select with Data' pressing that should import all the controls themed and their respective properties data.
With that done you should now have a theme overriding everything either replicating the default theme or the editor theme respectively. Save the theme.